1. Field of the Invention
The invention relates to a method for cleaning textiles in FCHC-free manner by means of solvents on a benzine basis.
The invention also relates to the use of such a method.
2. Description of the Prior Art
Finally, the invention also relates to an apparatus for cleaning textiles by means of FCHC-free solvents on a benzine basis comprising a cleaning machine, distillation section, recovery section and drier.
Generally, in such a cleaning plant the drying takes place (after transferring the material from the cleaning machine) by means of hot air; the textile material in particular predried by spinning in a drum in the cleaning machine (for example down to 11% residual moisture content) is further dried and the cleaning agent is recovered from the solvent-charged air by distillation and condensation.
However, particular safety precautions are necessary here because the solvent on a benzine basis involves a considerable danger of explosion, at the least from the flashpoint of the solvent (71.degree. C.) used upwards. Also, the operations under vacuum necessary because of this are very complicated. FCHCs are however allowed for only a short period and the use of PER involves increasingly high demands on the apparatus quality, and consequently both the FCHC-operated and the PER-operated machines must be replaced or at least considerably modified. In addition, with all existing machines and the cleaning agents used therein a practically 100% distillation was necessary due to the considerable contamination of the cleaning agent.
Also known is a method for dry cleaning with a hydrocarbon having a low flashpoint (41.degree. C.) and high vapour pressure (EP 90 119 398.7). A so-called dry-to-dry cleaning machine is described, i.e. a machine in which both washing and drying is carried out. With this type of solvent, for safety, technical, humane-ecological and ecological reasons reloading in the moist state is not compatible with European standards, in particular German standards. In this case hot air is forced in between the washing bath and the dry conduit and the evaporated solvent condensed for recovery. Before this solvent recovery step a partial vacuum is generated and an inert gas introduced. The inert gas is however introduced into the washing bath until the oxygen density of a mixture containing a solvent assumes a value beneath a predetermined limit value. After the introduction of the inert gas into the washing bath (reduction of the oxygen density) washing, centrifuging and finally drying are carried out.